Regarding dental treatment, an ultrasonic scaler is now practically used for removing plaque or the like by using ultrasonic vibration. In the oral cavity, a bacterium grows proliferously on an exposed portion of the dental implant or the like. When cleaning the exposed portion by an ultrasonic scaler, a vibratory chip of the ultrasonic scaler may touch with the surface of the implant, and the erosion of the exposed portion conversely goes from bad to worse by the touching.
To resolve such a problem, an ultrasonic cleaning device is suggested (for example as shown in Patent Documents 1 and 2) for cleaning the surface of teeth or dentures in a non-contact manner by propagating ultrasonic waves through a cleaning-liquid. Patent Document 1 shows an ultrasonic cleaning device in which a cleaning-liquid is supplied to a nozzle consisting of an ultrasonic-emitting surface. The nozzle tip-end touches the surface of the teeth or the like, and the cleaning-liquid is discharged through it, thus forming a channel for the propagating ultrasonic waves. The ultrasonic cleaning device has different functions, i.e. a cleaning-liquid reserving mode for reserving the liquid within the nozzle, an ultrasonic cleaning mode, and a high-pressure cleaning mode are performed repeatedly for efficient cleaning.
Patent Document 2 shows an ultrasonic cleaning device in which a concaved part for reserving the liquid is provided in the center of a head on which the brush is placed. An ultrasonic transducer is provided adjacently at the bottom of the concaved part. The concaved liquid-reservoir part comprises a liquid-outlet for supplying the liquid and a discharge inlet for discharging the liquid.